Sealant deploying apparatus and method

ABSTRACT

There is disclosed a road crack repair system for mounting on a vehicle. The system includes a sealant applicator that is positionable in front of the vehicle, the sealant applicator having a sealant outlet for discharging a molten sealant product above a crack in a road surface, and a trowel that is adjacent the sealant outlet and is arranged to contact the road surface and spread sealant product into and over the crack; a vessel within which to store a molten sealant product, and a conduit for delivering sealant product from the vessel to the sealant outlet; a support that is arranged to support the applicator in front of the vehicle with the trowel in contact with the road surface; and a control system that is operable by an operator to displace the applicator along road surface to follow a crack with advancement of the vehicle in a forward direction.

FIELD OF THE INVENTION

The invention relates to a method and apparatus for deploying sealantonto a road to seal cracks in the road.

BACKGROUND OF THE INVENTION

Road maintenance is an on-going activity to ensure roads remain suitablefor carrying traffic. The processes and equipment involved inmaintenance depend on the nature of damage to the road surface. Forexample, where a road surface has suffered delamination or fatigue, itmay be necessary to remove the damaged sections of roads and replacingwith an asphalt patch.

Cracks are typically narrow and very long, and therefore make up arelatively small proportion of the road surface. Removal and replacementof a section of road in which the only damage is a crack is noteconomical. Furthermore, the time and the size of the equipmentinterfere with flow of traffic, often causes excessive trafficdisruption. Cracks may branch and increase in size to the extent thatthe section of road needs to be replaced. However, in most cases, crackscan effectively be repaired with a bitumen-based sealant that fills thecrack and prevents further damage.

It is known to repair cracks using a vehicle that carries sealant, whichis deployed rearwardly from the vehicle to a hand held tool controlledby a worker walking behind the vehicle. The vehicle travels forwardslowly so that the process is substantially continuous.

A worker trailing the repair vehicle is exposed to on-coming traffic andthe risk that stray traffic could accidentally drive into the worker andthe repair vehicle. Although the risk is small, the consequences of suchan event occurring can be fatal.

SUMMARY OF THE INVENTION

The present invention provides a road crack repair system for mountingon a vehicle, the system comprising:

a sealant applicator that is positionable in front of the vehicle, thesealant applicator having a sealant outlet for discharging a moltensealant product above a crack in a road surface, and a trowel that isadjacent the sealant outlet and is arranged to contact the road surfaceand spread sealant product into and over the crack;

a vessel within which to store a molten sealant product, and a conduitfor delivering sealant product from the vessel to the sealant outlet;

a support that is arranged to support the applicator in front of thevehicle with the trowel in contact with the road surface; and

a control system that is operable by an operator to displace theapplicator along road surface to follow a crack with advancement of thevehicle in a forward direction.

In certain embodiments, the applicator has a leading end and a trailingend, the sealant outlet is positioned forwardly of the trailing end, andat least part of the trowel is positioned behind the sealant outlet suchthat as the applicator is moved forwardly with the leading endencountering an exposed crack first, sealant is discharged from theoutlet in front of the trowel.

In some embodiments, the trowel is in the form of a ring, and, in use,the sealant outlet discharges sealant product into the ring to form areservoir of molten sealant product that is then spread into and overthe crack by displacement of the ring.

The applicator can include a reservoir heater for heating sealant withinthe reservoir.

In some embodiments, the heater in the form of a resistive heatingelement that extends circumferentially around the ring.

The applicator may include one or more air jets that each direct an airstream in front of the leading end of the trowel for blowing loosedebris out of the crack.

The applicator can be movable transversely and longitudinally withrespect to the vehicle, and can also be rotatable, such that theapplicator can be moved along a crack and orientated with its leadingend toward the section of crack to be sealed.

In some embodiments, the trowel can be displaced along an axis that isapproximately perpendicular to the road surface when the trowel is incontact with the road surface to accommodate variations in the roadheight.

In some embodiments, the trowel can be pivoted on one or more axes thatare approximately parallel to the road surface when the trowel is incontact with the road surface to accommodate variations in the roadpitch.

In embodiments in which the trowel is in the form of a ring, theapplicator may include a flange that projects radially outwardly fromthe ring on at least the leading end, the flange acts as a skid tofacilitate movement of the ring and accommodate variations in the roadpitch and/or height.

The support may be in the form of a frame on which the applicator ismounted, the frame being mountable to the front of the vehicle.

The frame can have a transverse rail on which the applicator is mounted;and a pair of longitudinal arms that support the transverse rail and, inuse, extend forwardly from the vehicle.

The road crack repair system can further comprise a first actuator fordisplacing the applicator in a transverse direction with respect to thevehicle, and one or more second actuators for displacing the applicatorlongitudinally with respect to the vehicle.

In embodiments in which the system includes the above described frame,the first actuator is arranged to displaces the applicator along thetransverse rail. Furthermore in embodiments in which the system includesthe above described frame, the second actuator is arranged to displacethe transverse rail longitudinally along the longitudinal arms.

The road crack repair system may further comprise a third actuator forrotating the applicator about an axis that is approximatelyperpendicular to the road surface when the trowel is in contact with aroad surface. In embodiments in which the system includes the abovedescribed frame, the third actuator is arranged to rotate the applicatorabout a plurality of axes that are all approximately perpendicular tothe transverse rail.

The road crack repair system may further comprise a fourth actuator fordisplacing the trowel along an axis that is approximately perpendicularto the road surface when the trowel is in contact with a road surface.In embodiments in which the system includes the above described frame,the fourth actuator is arranged to displace the trowel relative to thetransverse rail in a plurality of planes that are perpendicular totransverse rail.

The road crack repair system may further comprises a fifth actuator forrotating the applicator about an axis that is parallel to the transverserail. In embodiments in which the system includes the above describedframe, the fifth actuator may be arranged to rotate the transverse railand the applicator relative to the longitudinal arms.

The longitudinal arms can be pivotally mounted to the vehicle, such thatthe frame is movable between a deployed position, in which thelongitudinal arms are generally horizontal, and a stowed position, inwhich the longitudinal arms are generally vertical.

The frame can further comprise a mounting beam that is mountable on thevehicle, and includes pivots on which proximal ends of the longitudinalarms are mounted.

The road crack repair system can further comprise a retraction devicefor moving the frame between the deployed and stowed positions. Incertain embodiments, the retraction device is in the form of a cablethat has one end attached to the frame, and a cable winch mounteddirectly or indirectly on the vehicle.

The road crack repair system can further comprise a boom that extendsover the cabin of the vehicle in the forward direction of the vehicle,the boom supporting the conduit.

In embodiments in which the system comprises a retraction device that isin the form of a cable, the boom also supports the cable winch.

In some embodiments, the frame further comprises a cross beam thatextends between the distal ends of the longitudinal arms.

The cross beam may be provided with one or more swivel caster wheelsthat, when the frame is in the deployed position, can contact the roadsurface and provide support to the frame. Preferably, the caster wheelsdepend from the cross beam.

In certain embodiments, the road crack repair system further comprises asurfactant discharge system that includes one or more spray nozzlesthat, in use, each spray a surfactant onto one of the road surface infront of one of the vehicle's tyres, or directly onto the tyres.

The control system can be operable to control any one or more of:

-   -   operation of the first actuator to displace the applicator        transversely with respect to the vehicle;    -   operation of the or each second actuator to displace the        applicator longitudinally with respect to the vehicle; and    -   discharge of molten sealant product from the sealant outlet.

Alternatively or additionally, the control system can be operable tocontrol any one or more of:

-   -   movement of the frame between the stowed and deployed positions;    -   rotation of the applicator and the transverse rail relative to        the longitudinal arms;    -   rotation of the applicator relative to the transverse rail,        which provides for rotation of the trowel when in contact with        the road surface;    -   discharge of surfactant from surfactant spray nozzles;    -   operation of the resistive heating element; and    -   operation of the air jets.

The control system may also include a joystick that is operable by anoperator to displace the applicator in transverse and longitudinaldirections relative to the vehicle.

In certain embodiments, the control system is also operable toautomatically rotate the applicator with displacement of the applicatorrelative to the vehicle such that the leading end of the applicator isorientated in the same direction as the displacement of the applicator.

The present invention may also provide a vehicle comprising the roadcrack repair system described previously.

The present invention may also provide a method of repairing a crack ina road surface, the method comprising:

-   -   using a vehicle to which a road crack repair system is mounted,        the system having a vessel, and a sealant applicator that has a        sealant outlet and a trowel;    -   preparing a molten sealant product in the vessel;    -   positioning the applicator in front of the vehicle;    -   bringing the trowel in contact with the road surface;    -   conveying the sealant from the vessel to the applicator;    -   discharging the sealant product from a sealant outlet of the        applicator above the crack; and    -   manipulating the trowel to spread sealant product into and over        the crack.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more easily understood, embodimentswill now be described, by way of example only, with reference to theaccompanying drawings, in which:

FIG. 1: is a front view of a vehicle provided with a road crack repairsystem according to a first embodiment of the present invention, shownwith the frame of the system in a stowed position;

FIG. 2: is a partial side view of the vehicle of FIG. 1;

FIG. 3: is a partial side view of the vehicle of FIG. 1, showing theframe between the stowed and deployed positions;

FIG. 4: is a partial front view of the vehicle of FIG. 1, also showingthe frame between the stowed and deployed positions;

FIG. 5: is a partial view of the frame of the system of FIG. 1, in whichthe applicator is in a stowed position;

FIG. 6: is a partial view of the frame of the system of FIG. 1, in whichthe applicator is in a deployed position;

FIG. 7: is a partial view of the frame of the system of FIG. 1, in whichboth the frame and applicator are in their respective deployed position;

FIG. 8: is a partial view of the vehicle and system of FIG. 1, in whichboth the frame and applicator are in their respective deployed position;

FIG. 9: is a schematic side view of the vehicle and system of FIG. 1;

FIG. 10: is a further partial view of the vehicle and system of FIG. 1,in which both the frame and applicator are in their respective deployedposition;

FIG. 11: is a partial view of the frame and applicator of FIG. 1, withthe trowel of the applicator raised from a road surface;

FIG. 12: is a partial view of the frame and applicator of FIG. 1, withthe trowel of the applicator in contact with a road surface;

FIG. 13: is an enlarged view of applicator of FIG. 12, showing thetrowel in contact with the road surface;

FIG. 14: is a partial perspective view of the vehicle of FIG. 1, showingthe front right wheel and a surfactant spray nozzle of the road crackrepair system;

FIG. 15: is a partial perspective view of the vehicle of FIG. 1, showingthe rear right dual wheels and a surfactant spray nozzle of the roadcrack repair system;

FIG. 16: is a schematic side plan view of an applicator of road crackrepair system according to a second embodiment of the present invention;and

FIG. 17: is a schematic side plan view of the applicator of FIG. 16,showing the inner working components thereof.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1, 2 and 9 show a vehicle 10 that is provided with a road crackrepair system 20. The repair system 20 has a sealant applicator 50 thatis able to be positioned in front of the vehicle 10.

In this embodiment, the vehicle 10 is a tray-truck type vehicle, havinga tray 12 supported on the vehicle chassis behind the driver's cabin 14.The system 20 includes a vessel 22 (shown in FIG. 9) within which amolten sealant product can be stored. The vessel 22 may include a heaterto melt the sealant product, or to maintain the sealant product in amolten state. The sealant product can be a bituminous product.

The repair system 20 has a support that is arranged to support theapplicator 50 in front of the vehicle 10. In this embodiment, thesupport is in the form of a frame 40. The system includes a controlsystem (not shown) that is operable by an operator to displace theapplicator 50 along road surface to follow a crack with advancement ofthe vehicle in a forward direction. In use, a conduit 24 deliverssealant product from the vessel 22 forwardly of the vehicle 10 to theapplicator 50 for application into and over the crack.

The system 20 mounted to the vehicle 10 in the manner described enablessealing of road cracks with the applicator being positioned in front ofthe vehicle, and thus in the path of the vehicle. An operator canoperate the system 20 from within the cabin 16, and thus not be exposedto traffic and other hazards.

As shown in FIGS. 3 to 9, the frame 40 is pivotally mounted beneath thefront of the cabin 14. The frame 40 can be pivoted between a stowedposition (shown in FIGS. 1 and 2), and a deployed position (shown inFIGS. 7 to 9). FIGS. 3 to 6 show the frame 40 intermediate the stowedand deployed positions. The stowed position is utilized when the vehicleis not being used for road repair activities, such as when parked orwhen driving between locations. The deployed position is utilized duringroad crack sealing activities.

The frame 40 includes a transverse rail 42 on which the applicator 50 ismounted, and a pair of longitudinal arms 44 that support the transverserail 42. As shown in FIGS. 8 and 9, when the frame is in the deployedposition the longitudinal arms 44 extend forwardly from the vehicle 10.

The applicator 50 can be movable transversely and longitudinally withrespect to the vehicle, and can also be rotatable, such that theapplicator can be moved along a crack to be sealed. This facilitatesrepairing of road cracks by moving the applicator 50 to along the crackas the vehicle progresses forward. As will be appreciated, road cracksare often serpentine, and can branch off into separate cracks.

In this particular embodiment, the applicator 50 is movable along thetransverse rail 42 in a direction that is transverse to the vehicle 10.Furthermore, the transverse rail 42 is movable along the longitudinalarms 44, such that the applicator is movable in a direction that islongitudinal to the vehicle 10 (and thus perpendicular to the transverserail 42). Thus, the applicator 50 is able to be moved to any locationthat is between the pair of longitudinal arms 44.

The road crack repair system 10 has a first actuator for displacing theapplicator 50 in the transverse direction. In this particularembodiment, the first actuator is in the form of a chain drive 38 a. Thesystem 10 also has one or more second actuators for displacing theapplicator 50 in the longitudinal direction. In this particularembodiment, the second actuator is in the form of a chain drive 38 b.The chain drives 38 a, 38 b are shown in FIG. 11.

The applicator 50 can be rotated with the transverse rail 42 on thelongitudinal arms 44. As can be appreciated from the Figures, theapplicator 50 is relatively tall and narrow. When the frame 50 is in thestowed position, the applicator 50 is rotated such that it lies with itslengthwise direction aligned with the longitudinal arms 44. Thisprovides for compact stowage of the applicator 50. However, when theframe 40 is in the deployed position for use in road repair activities,the applicator 50 needs to be rotated such that the applicator 50 cancontact the road surface, as will be discussed in further detailsubsequently. The system 20 includes an actuator to rotate theapplicator 50 such that its lengthwise direction is perpendicular to thelongitudinal arms 44. In this embodiment, the actuator is in the form ofa chain drive 38 c, which is shown in FIG. 11. Thus, the chain drive 38c rotates the applicator 50 about an axis that is parallel to thetransverse rail 42.

The road crack repair system 20 has a boom 30 that extends over thecabin 14 of the vehicle 10. The boom 30 supports the conduit 24 abovethe cabin 14 and forwardly out over the frame. Supporting the conduit 24on the boom 30 assists in minimizing the possibility of damage to theconduit 24. However, it will be appreciated that in some alternativeembodiments, the conduit could be supported beneath the floor of thevehicle, or to the side of the vehicle.

A retraction device is provided to move the frame 40 between the stowedand deployed positions. In this embodiment, the retraction device is inthe form of a cable 32 a that has one end attached to the frame, and acable winch 32 b mounted directly or indirectly on the vehicle 10. Inthis embodiment, the cable winch 32 b is mounted on the boom 30.

The frame 40 further has a mounting beam 46 that is mounted to thevehicle 10. The longitudinal arms 44 are pivotally mounted to themounting beam 46. Furthermore, a cross beam 48 extends between thedistal ends of the longitudinal arms 44 to provide rigidity to thelongitudinal arms 44.

The cross beam 48 has a pair of swivel caster wheels 49 that, when theframe 40 is in the deployed position, can contact the road surface andprovide support to the frame 40. As shown in FIG. 8, the caster wheels49 depend from the cross beam 48.

As will be appreciated, the use of the frame 40 provides for safety ofpedestrians and property. The applicator 50 can only be moved within theboundary of the frame 40 (defined by the vehicle 10, the longitudinalarms 44, and the cross beam 48). Thus, it is unlikely that a pedestriancould stray into the path of the moving applicator 50.

As described previously, when the frame 40 is in the deployed positionfor use in road repair activities, part of the applicator 50 contactsthe road surface. Detail of the applicator 50 is illustrated in FIGS. 11to 13. The applicator 50 includes a sealant outlet 52 for discharging amolten sealant product received via the conduit 24 above a crack in aroad surface, and a trowel 54 that is adjacent the sealant outlet. Thetrowel 54 is arranged to contact the road surface and spread sealantproduct into and over the crack. To this end, the trowel 54 levels thesealant to the road surface level. The trowel 54 can also contain the“width” of the sealant over the top of the crack.

The applicator 50 has a leading end L and a trailing end T. The sealantoutlet 52 is positioned forwardly of the trailing end T, and part of thetrowel 54 is positioned behind the sealant outlet 52. In this way, asthe applicator is moved forwardly with the leading end L encountering anexposed crack first, sealant is discharged from the outlet 52 in frontof the trowel 54.

As is most evident from FIG. 13, in this embodiment the trowel 54 has aring shape. Sealant product is discharged from the sealant outlet 52into the ring to form a “reservoir” of molten sealant product that isthen to be spread into and over the crack by displacement of the trowel54. A reservoir heater, which in this embodiment is in the form of aresistive heating element 56, provides heat to the reservoir, whichensure that the reservoir remains in a molten state. The resistiveheating element is coiled circumferentially around the trowel 54.

A pair of air jets 58 that each direct an air stream are provided to theapplicator 50 in front of the leading end L. The air jets blow loosedebris out of the crack immediately before sealant product is applied.This reduces the chance of the sealant product being lifted from thecrack after application.

As described previously, the applicator 50 is movable transversely andlongitudinally with respect to the vehicle. In addition, the applicator50 is rotatable, such that the applicator 50 can be moved along a crackand orientated with its leading end L toward the section of crack to besealed. To this end, an actuator is provided to rotate the applicator 50about an axis that is approximately perpendicular to the road surfacewhen the trowel 54 is in contact with a road surface. This actuator canbe in the form of a belt drive 38 d. Since the applicator 50 issupported on the transverse rail 42, which is rotatable and displaceablerelative to the longitudinal arms 44, the belt drive 38 d can rotate theapplicator 50 about a plurality of axes that are all approximatelyperpendicular to the transverse rail 42.

The road crack repair system 10 may has an actuator for displacing thetrowel 54 along an axis that is approximately perpendicular to the roadsurface when the trowel 54 is in contact with a road surface. In theFigures, this actuator is obscured by the frame components and theapplicator. In FIG. 11, the trowel 54 is shown slightly raised from theroad surface, and in FIGS. 12 and 13, the trowel is shown in contactwith the road surface. In the illustrated embodiment, the entireapplicator is movable perpendicular to the road surface. Since theapplicator 50 is supported on the transverse rail 42, which is rotatableand displaceable relative to the longitudinal arms 44, this actuator isarranged to displace the applicator, and thus the trowel 54, relative tothe transverse rail 42 in a plurality of planes that are perpendicularto transverse rail 42.

The applicator 50 includes a flange 59 that projects radially outwardlyfrom the trowel 54 on at least the leading end L, the flange 59 acts asa skid to facilitate movement of the trowel 54 over the road surface andaccommodate variations in the road pitch and/or height. The flange 59extends around approximately three quarters of the circumference of thetrowel 54, and thus provides a skid to forwards and sidewards movementof the trowel 54 over the road surface.

The trowel 54 can be displaced along an axis that is approximatelyperpendicular to the road surface when the trowel is in contact with theroad surface. This enables the trowel to accommodate variations in theroad height. To this end, the trowel 54 is mounted on three legs 60 thatcan each be retracted up into the applicator 50. Thus, as the trowel 54encounters a bump in the road surface, the trowel 54 can rise and fallto pass over the bump.

The trowel 54 can also be pivoted on one or more axes that areapproximately parallel to the road surface when the trowel 54 is incontact with the road surface to accommodate variations in the roadpitch. To this end, each of the three legs 60 is connected to the trowel54 by a pivot joint. One of the legs 60 a is connected to the trowel 54at its leading end L, and enables the trowel 54 to pivot on a firstaxis. The other two legs 60 b, 60 c are spaced equidistantly from leg 60a, and enable the trowel 54 to pivot on a second axis, which isapproximately perpendicular to the first axis.

The road crack repair system 20 further has a surfactant dischargesystem that includes a surfactant reservoir 62 and spray nozzles 64that, in use, each spray a surfactant onto the road surface, asindicated by the arrows S, in each of FIGS. 9, 14 and 15. The spraynozzles 64 are positioned to spray surfactant in front of each of thevehicle's tyres W. The surfactant wets the road surface in advance ofthe vehicle's tyres, and also wets the sealant that has been applied tothe crack. The surfactant reduces the tendency of sealant to stick tothe vehicle's tyres. In this particular embodiment, the width of thespray at the road surface is wider than the tyre tread to accommodateturning of the vehicle as it is driven forward. In some alternativeembodiments, the surfactant discharge system may be arranged to spraysurfactant directly onto the vehicles tyres.

As noted previously, the control system can be operated from within thecabin 14 of the vehicle 10. This enables monitoring of the position ofthe applicator 50 and adjustment by direct visual inspection by anoperator without the need for remote cameras and video equipment. Thisis particularly beneficial because an operator can clearly see a crackin the road and guide the applicator 50 accordingly. It will beappreciated that the direct visual inspection can be augmented with acamera and video equipment. This may be of assistance where the operatoris within the cabin 14 of the vehicle 10, and use of the applicator 50immediately in front of the vehicle 10 is sought.

As will be appreciated, relying solely on a camera and video equipmentto observe a road crack and to operate the applicator has thedisadvantage of narrowing the field of vision. This impairs theoperators ability to accurately and rapidly control of the applicatorrelative to a crack in a road.

The control system is operable to control any of the followingactivities of the road crack repair system 20:

-   -   operation of the chain drive 38 a, to displace the applicator        transversely with respect to the vehicle, and thus along the        transverse rail 42;    -   operation of the or each chain drive 38 b to displace the        applicator longitudinally with respect to the vehicle, and thus        displace the transverse rail 42 along the longitudinal arms 44;    -   discharge of molten sealant product from the sealant outlet 52;    -   movement of the frame 40 between the stowed and deployed        positions, and thus operation of the retraction device;    -   rotation of the applicator 50 and the transverse rail 42;    -   rotation of the applicator 50 relative to the transverse rail        42;    -   discharge of surfactant from surfactant spray nozzles 64;    -   operation of the resistive heating element 56; and    -   operation of the air jets 58.

The system 20 has a pump (not shown) for supplying molten sealantproduct from the vessel 22 into the conduit 24. The control system isalso operable to control operation of the pump. To this end, the controlsystem can adjust the pump flow rate in proportion to the speed of theapplicator 50. This ensures that the volume of sealant within thereservoir formed by the trowel 54 on the road surface is maintained atan optimal level.

In addition, the control system is configured such that the operator canhave the system 20 automatically commence discharge of sealant from thesealant outlet 52 with initial movement of the trowel 54 on the roadsurface. As will be appreciated, there is a need to stop sealantdischarge from the sealant outlet 52 as the trowel 54 approaches the endof the section of crack to be sealed, and the trowel 54 lifted from theroad surface. In use, as the trowel 54 approaches the end of a sectionof crack, the operator uses the control system to stop discharge ofsealant product from the sealant outlet 52. Ideally, the reservoirwithin the trowel 54 is depleted at the end of the crack.

A valve (not shown) is provided in the conduit 24 immediately upstreamof the sealant outlet 52, which enables the conduit 24 to be closed toprevent sealant dripping from the outlet 52.

The control system may also include a joystick (not shown) that isoperable by an operator from within the cabin to displace the applicator50 in transverse and longitudinal directions relative to the vehicle. Incertain embodiments, the control system is also operable toautomatically rotate the applicator 50 with displacement of theapplicator 50 relative to the frame 40 such that the leading end L ofthe applicator 50 is orientated in the same direction as thedisplacement of the applicator 50. This ensures that the air jets 58 aredirecting their respective air streams into the crack.

A single operator can use of the vehicle 10 and system 10 to repair roadcracks. In particular, an operator can drive the vehicle 10 and operatethe system 20. For safety and accuracy of the repair, this wouldtypically involve stopping the vehicle 10 with the frame 40 over asection of road to be repaired. The crack (or cracks) within thatsection are then repaired, and the vehicle 10 is then moved on to thenext section of road to be repaired. In this way, operation of thevehicle 10 and system 20 are sequential.

In some embodiments, the frame can be configured to be shiftedtransversely on one or both sides of the vehicle to be partially offsetrelative to the path of the vehicle.

FIGS. 16 and 17 show an applicator 150 of a road repair system accordingto a second embodiment. The applicator 150 is supported by a support(not illustrated in FIGS. 16 and 17) such that, in use, the applicator150 is able to be positioned ahead of the vehicle to which the roadrepair system is mounted. In this embodiment the road repair system alsoincludes a support arm 152 that is connected to the support.

The support arm 152 includes a guide rod 156 to which bushes 154 areconnected and extend outwardly to a housing 160. The housing 160 isrotatably mounted to the bushes, but the bushes 154 and housing 160comprise a unit that is slidable along the guide rod 156. Movement alongthe guide rod 156 is controlled by a motor 158 that enables the housing160 to be raised or lowered relative to the support arm 152 and hencethe road.

A top end of the housing 160 is closed and includes an upwardlyextending boss 162 to which is connected a swivel leg 164 which, in turnis linked to the sealant conveying hose 124. The swivel leg 164 enablesthe housing 160 to rotate relative to the sealant conveying hose 124.

A lower end of the housing includes an outwardly extending flange 196and is closed by cover 170 and includes and downwardly extending neck172 that defines a shoulder 173.

The neck 172 has a generally cylindrical profile and is closed at itsend, but includes an aperture 174 formed in a curved surface of the neck172.

A tube 176 extends from the boss 162 and terminates at the shoulder 173such that sealant is supplied from the tube 176 into the neck 172 toflow from the applicator 150 via the aperture 174.

Sealant flow is controlled by adjusting location of the tube 176 withinthe neck 172. Accordingly, sealant flow is stopped by actuating a motor180 to lower the tube 176 such that the tube 176 abuts the closed end ofthe neck 172, thereby closing the aperture 174.

In order to ensure that an appropriate amount of sealant runs into acrack (owing to differences in crack width and depth), sealant exitingaperture 174 falls into a reservoir formed by a trowel 188 in the formof a ring. The trowel 188 is linked by rods 190 to a further ring 192that extends about the outside of the housing 160. The trowel 188 isbiased by a spring 194 into contact with the road by forcing the ring192 downwardly. Movement of the ring 192 downwardly is limited by theflange 196.

The applicator further includes an air jet for blowing air into a crackto remove loose debris prior to filling the crack with the sealant. Theair jet is provided by an air line 182 that extends through an upper endof the housing and terminates at an upper manifold 184. The housingfurther includes a lower manifold 184 from which extends an air outletpipe 186. A worker is able to control the direction of an air jet bycontrolling rotation of the housing 160 relative to the support arm 152via motor 166 and toothed gears 68, one of which is fixed to an upperportion of the housing 160.

1. A road crack repair system for mounting on a vehicle, the systemcomprising: a sealant applicator that is positionable in front of thevehicle, the sealant applicator having a sealant outlet for discharginga molten sealant product above a crack in a road surface, and a trowelthat is adjacent the sealant outlet and is arranged to contact the roadsurface and spread sealant product into and over the crack; a vesselwithin which to store a molten sealant product, and a conduit fordelivering sealant product from the vessel to the sealant outlet; asupport that is arranged to support the applicator in front of thevehicle with the trowel in contact with the road surface; and a controlsystem that is operable by an operator to displace the applicator alongroad surface to follow a crack with advancement of the vehicle in aforward direction.
 2. A road crack repair system according to claim 1,wherein the applicator has a leading end and a trailing end, the sealantoutlet is positioned forwardly of the trailing end, and at least part ofthe trowel is positioned behind the sealant outlet such that as theapplicator is moved forwardly with the leading end encountering anexposed crack first, sealant is discharged from the outlet in front ofthe trowel.
 3. A road crack repair system according to claim 1, whereinthe trowel is in the form of a ring, and, in use, the sealant outletdischarges sealant product into the ring to form a reservoir of moltensealant product that is then spread into and over the crack bydisplacement of the ring.
 4. A road crack repair system according toclaim 3, wherein the applicator includes a reservoir heater for heatingsealant within the reservoir.
 5. A road crack repair system according toclaim 2, wherein the applicator may include one or more air jets thateach direct an air stream in front of the leading end of the trowel forblowing loose debris out of the crack.
 6. A road crack repair systemaccording to claim 2, wherein the applicator is movable transversely andlongitudinally with respect to the vehicle, and is also rotatable, suchthat the applicator can be moved along a crack and orientated with itsleading end toward the section of crack to be sealed.
 7. A road crackrepair system according to claim 1, wherein the support is a frame onthe applicator is mounted, the frame being mountable to the front of thevehicle.
 8. A road crack repair system according to claim 7, wherein theframe comprises: a transverse rail on which the applicator is mounted;and a pair of longitudinal arms that support the transverse rail and, inuse, extend forwardly from the vehicle.
 9. A road crack repair systemaccording to claim 1, further comprising: a first actuator fordisplacing the applicator a transverse direction with respect to thevehicle, and one or more second actuators for displacing the applicatorlongitudinally with respect to the vehicle.
 10. A road crack repairsystem according to claim 1, further comprising a third actuator forrotating the applicator about an axis that is approximatelyperpendicular to the road surface when the trowel is in contact with aroad surface.
 11. A road crack repair system according to claim 1,further comprising a fourth actuator for displacing the trowel along anaxis that is approximately perpendicular to the road surface when thetrowel is in contact with a road surface.
 12. A road crack repair systemaccording to claim 1, further comprising a surfactant discharge systemthat includes one or more spray nozzles that, in use, each spray asurfactant onto one of the road surface in front of one of the vehicle'styres, or directly onto the tyres.
 13. A road crack repair systemaccording to claim 9, wherein the control system is operable to controlany one or more of: operation of the first actuator to displace theapplicator transversely with respect to the vehicle; operation of the oreach second actuator to displace the applicator longitudinally withrespect to the vehicle; and discharge of molten sealant product from thesealant outlet.
 14. A road crack repair system according to claim 13,wherein the control system is operable to automatically rotate theapplicator with displacement of the applicator relative to the vehiclesuch that the leading end of the applicator is orientated in the samedirection as the displacement of the applicator.
 15. A vehicle forrepairing a road surface comprising a road crack repair system mountedon the vehicle, the system comprising: a sealant applicator that ispositionable in front of the vehicle, the sealant applicator having asealant outlet for discharging a molten sealant product above a crack ina road surface, and a trowel that is adjacent the sealant outlet and isarranged to contact the road surface and spread sealant product into andover the crack; a vessel within which to store a molten sealant product,and a conduit for delivering sealant product from the vessel to thesealant outlet; a support that is arranged to support the applicator infront of the vehicle with the trowel in contact with the road surface;and a control system that is operable by an operator to displace theapplicator along road surface to follow a crack with advancement of thevehicle in a forward direction.